Background A high incidence rate of hepatitis B or C virus infection is found among thalassemia children in Indonesia. This may influence deferiprone effectiveness. Objective To determine the effectiveness of deferiprone in thalassemia children with or without hepatitis B or C virus infection. Methods A non-randomized clinical study was performed at Thalassemia Center Jakarta. Subjects were thalassemia children with serum ferritin level > 1000 ng/mL who had hepatitis B or C virus infection. A match control pair was recruited based on similar duration of transfusion therapy, thalassemia type, and initial serum ferritin level. All subjects received initial deferiprone dose of 50 mg/kg/day for 3 months. Those whose ferritin decreased 2:: 10% continued to receive deferiprone of 50 mg/kg/day for the following 3 months. Otherwise, deferiprone dose was adjusted to 75 mg/kg/day. Results Forty-eight subjects were recruited. After 3 months of treatment, 16/24 subjects without and 6/24 subjects with hepatitis B or C had their ferritin level decreased 2:: 10%. Mean ferritin serum level of all subjects after 6 months was significantly reduced from 4734 (SD 2116) to 3695 (SD 1709) ng/mL. Lower mean deferiprone dose, lower mean post- study ferritin serum level and higher mean percentage of ferritin serum level decrement were found in subjects without hepatitis B or C infection than those with infection. Conclusions Deferiprone 50-7 5 mg/kg/day for 6 months is effective in reducing serum ferritin level of thalassemia major children; it is more effective in thalassemia children without hepatitis B or C virus infection.